The overall objective of our research is to understand how regulatory proteins interact with DNA and therefore control gene expression. The methodology has involved first chemical and enzymatic synthesis of DNA sequences involved in gene control. We then manipulate and modify these sequences and measure how these changes alter gene expression. Earlier work from this laboratory has defined the DNA sites recognized by lac repressor on lac operator. Future research will be directed toward examining how these sites relate to control in the lac operon. Additionally we want to design an operator that will bind lac repressor even more tightly than the naturally occuring operator. Another system we will probe extenively is the interaction of the lambda rightward promoter with cI repressor, cro repressor and E. coli RNA polymerase. Our objective is to probe how all three proteins interact cooperatively or antagonistically with the same control region. Finally we will be examining the interaction of T-antigen with its binding site on SV40 DNA. For both the lambda and SV40 projects, the DNA synthesis is approximately 75% complete.